constrain proporations with php

I am making a website for myself and I have news displayed on the website. Along with the news is a top story displaying an image based on that story. I have so much space to place that image without it being any bigger or the design will look wacked up. Since the images provided are located on the server's of the people submitting news, I have no control over the size.

I was wondering if there was a way to take the resized width of the image that I set if it is bigger than the table width and determine the proper height? I see that Photoshop has the ability to determine the height based of a specified width. Maybe there's a painless way with PHP or a mathematical equation to accomplish this. I was wondering if anyone had an answer to this issue of mine. Thank you.

All it does is to find the porotional right height.. it wouldn't work for all images, because all images aren't proportional..

take a look at this:
800 / 1,333 = 600,15003750937734433608402100525
1024 / 1,333 = 768,19204801200300075018754688672
640 / 1,333 = 480,1200300075018754688672168042

uh, or, something..

I just finished reading an article on resizing images using Mogrify... I thought it was a good solution. Basically the script executes a command-line function to resize the image based on the arguments passed to it.

But this wasn't a viable solution for people that use free-hosts or for hosts that do not allow command-line execution.

A user posted a comment on how he did it without executing any external programs. Check out his comment and his site for the source.

Basically, what he does it sets a maximum width/height that any image may be, and resizes the uploaded image based on a proportional calculation.

Oh this script just might work out. Thanks for the support.